harphunt

I'm assuming the glow plug is red/positive when starting an .049 cox, correct? Thanks.

peace

mikegordon10

Makes no difference. It will work just fine either way.

ffkiwi

Not quite sure what you are asking here-the polarity-as in 'negative/positive' lead is irrelevant when powering a glowplug or glowhead. What IS important both for ease of starting and glowplug life is the voltage and current-plugs can be rated at 1.5V, 1.5-2V, 2V or 1.5-3V depending on the manufacturer. This is not to be confused with plug heat -a 'hot' plug is not one that runs at 3V! Cox heads are rated at 1.5V-and originally intended for operation on a decent sized 1.5V dry battery. A 'glow starter' (or 'stick' as some refer to them) is powered by a single NiCad or NiMH battery of 1.25V-which is generally a little low for a Cox (plus you need an adaptor to fit the Cox head). A lot of people use glow drivers-these apply pulse of current and voltage to the plug-so it 'sees' an average of 1.5-2V and the appropriate current-and these are adjustable by the user via a control knob on the power panel.

How much current? Impossible to be specific-it will vary from plug type to plug type, from brand to brand, and as the plug ages. It will also vary depending on the condition of the engine-a flooded engine will have the plug element dowsed in liquid fuel-and will draw more current. Typically a plug will draw something of the order of 2-4amps when 'lit'. If you're asking what colour the plug should glow then the correct colour is bright orange red-and ideally should be checked both under inside lighting and with the plug or glowplug removed from the engine. In bright outside sunlight you can't see the colour properly, and you can't check simply by looking through the exhaust port (though this WILL tell you if you have too much current-the plug should never glow yellow-this is passing too much current and risks burning it out. Conversely-dull red is not hot enough to ensure reliable starting.

Does this help?

ChrisM
'ffkiwi'

mikegordon10

Well so much for the KISS principle.

ffkiwi

So you favour ignorance then?

ffkiwi

harphunt

Now, now...

Mikegordon, that is what I was wondering. Thanks. ffkiwi, thanks for your extended response, but planned on using 1.5v lantern battery like when I was a kid.

I do have another question, though. On my RC power panel, one can hook up clips for glow heat, but it is measured in d.c. amperes. Is this too hot for a cox glow plug? What would I set it at? Thanks, again.

peace

mikegordon10

Why would you want to call the OP ignorant? Just answer his question without try to impress anyone here.

harphunt

I think he meant you Mike... By the way, lantern batteries are 6volt. Here I go...

peace

mikegordon10

Yes your power panel will do this job nicely but as far as what to set it at your going to have to hook it up (outside of the engine) to the same type of glow plug you want to use and look at the filament to see what color it's glowing when the power panel is connected.
Like our friend from down under has said you don't want it dull red or white hot. Start with the control knob on the Power Panel turned down all the way and then slowly advance it to like a bright orange. Be careful it's easy to burn out Cox Glow Heads and they ain't cheep. Look at the meter on the power panel and note where the needle is. This would be the setting for that type of plug. There are other types of glow plugs that can be purchased that work with Cox engines available from after market sources. One that comes to mind is Nelson but there are others. Do a Google search and see what you can find.

mikegordon10

No, he was saying that you needed an education in glow plugs and without him you would remain ignorant.

ffkiwi

Actually the comment was aimed at MG in response to the KISS comment, not the original poster. I surmised that if the original poster had to ask about plug polarity he didn't have a lot of knowledge about plugs.

Moving on-and turning the heat down (.....deliberate pun) a lantern battery is a good choice for safe (as opposed to economic) operation of Coxes. When I was a kid in the 60's I used to use what were called 'bell' batteries-obtained from a mate whose father worked for what was then the 'P&T' department-'Post and Telegraph' and apparently these things were used extensively in telephone exchanges and changed regularly. The used ones had plenty of life left in them, and if connected in parallel you were set up for about a year. Though still 1.5V, they were massive things about 9" tall and about 2-1/2" in diameter weighing a couple of pounds apiece-and AFAIK no longer produced-but they had the capacity to deliver the amps needed by the plug for extended period without complaint-something that a D size dry cell will stumble over. The only issue with using 1.5V dry cells is cost vs life-and I suppose that depends on how much flying you do......I note that Cox International now offer a twin, parallel wired battery box for 2 D cells that may be a cheaper option in use than a lantern battery

As MG as already noted the procedure for checking out your Cox head on a glow driver I don't need to repeat it again-but simply add the comment that the meter deflection is probably the key-note where the needle sits when the plug is glowing the right orange colour. I've never seen a power panel where the meter actually stated the true amps-they are invariably calibrated in either just numbers (like 1-5) and/or a series of coloured bands. In any case glowdrivers/power panels are supplying a pulsed current to the plug so the meter is only showing an average position (in some panels you can hear the pulsing as a background faint high pitched tone emanating from the innards of the panel.

I invariably use a power panel for starting glowplug engines-though I keep a 2V Gates cell in the box for emergency use (but these 2V cells are not suitable for using on a Cox without a dropping resistance)-my personal experience with the single cell NiCd/NiMH glowstarters is that they are a bit marginal on heating the plug-and I've tried a number of versions. In any case, as noted in my earlier response, you can't use them on a Cox (or any other type of glow head) without an additional adapter

ChrisM
'ffkiwi'

SGC

Actually the No6 cells as used in telephone systems are still available if you search about, my local hobby shop still sells them.

ffkiwi

Good heavens-I wonder what their main use is these days-I used to stagger over to the pits when I was a junior with 4 of them wired in parallel in a wooden milk bottle holder (made at school woodwork class)-but they were the bees knees for starting Coxes-even second hand ones............

ChrisM
'ffkiwi'

SGC

Chris,
I believe they are only made for the hobby industry Chinese manufacturures designation GT R40, imported to Australia by lion electronics http://www.tnet.com.au/~lion/Battery_Chargers.htm scroll down to dry cells.

ffkiwi

OK-I didn't think in this era of glow drivers, glow igniters etc there'd be enough of a market to justify manufacture of such a dry cell. The last time I can recall buying one (probably the only one I ever purchased new) was ca. 1973 or 74-I can't remember if it had screw terminals or the brass Fahnstock clips you pressed down to insert a wire into. I do recall Cox marketing dry cell starter batteries that were rectangular-about 6"x2"x1"-well into the eighties-and perhaps later-but these were much much smaller than the big cylindrical bell batteries I'm referring to................

ChrisM
'ffkiwi'

SBS_Pilot

Well, at least one distributer sells them in 20' containers.... www.alibaba.com/product-gs/586704390/1_5V_high_pacity_R40_battery.html


There was a lot of sellers of this kind of batterys at AliBaba.com (sort of a marketplace for Chinese producers to find distributors all over the world), so I guess there must be some other obscure use for this battery.

ffkiwi

.....that's the one all right-and my memory of the dimensions and weight wasn't too far out either-for something I last handled nearly 40 years ago! Mind you the ones of my youth were the classic 'Ever-ready' red and blue casing with the cat, the lighting bolt and the figure 9 emblem.
40Ah?-no wonder they lasted and lasted (and even the run down rejects that we got for nothing would have had quite a lot of residual capacity!)

ChrisM
'ffkiwi'

pmerritt

My Feedback: (118)

Well from us dumb Texans...you can hook a whole bunch of them there 6 volt lantern batteries together and do some serious cat fishing with them.  It won't take a fellow long to realize that hooking a 6 volt battery to a glow plug will break the wallet pretty quick!

Rubbernecker

My Feedback: (22)

I have used the "D" size Gates 2 volt battery for years with no problem at all. Cox, Glo-Bee and Nelson plugs.

John

ffkiwi

I use a D-size one on GloBee plugs, but only on them-I don't know how you're managing to safely use one with Cox heads unless you've got some kind of dropping resistance set up-or suitably long leads to drop the voltage down a bit. I've yet to find a power panel that has the grunt to light a GloBee to an acceptable heat-and I'm not going to trawl the market testing each one till I do.

'Lantern' battery to me does not necessarily mean a 6V unit-there used to be 3V and 4.5V ones (the latter commonly used for cycle headlamps-internally it was 3x 1.5V cells, just as the current 6V ones are 4x 1.5V roughly D size cells-growing up, a lantern battery was simply a dry cell packaging that was not a simple cylindrical AA, C, or D battery-and not the small rectangular 9V stacked type.

ChrisM
'ffkiwi'

gcb

The batteries made from "D" cells used to come in 1.5V. (parallel) or 6V (series). Of course we used the 1.5V. ones.

Before that we used "doorbell" batteries that were about 6" tall and about 2" in diameter. I used two of those hooked in parallel to get 1.5V and would last at least a year. Also used wire and alligator clips for hookup.

BTW, first time I tried to start an engine (Space Bug Jr. ~ 1954) I was inside and attempted to use a model train transformer (didn't yet have a battery). I did not realize that the xformer turned on at ~13VAC. Glow head went off like a flash bulb and I went to my LHS to get another plug and a battery.

George

Jim Thomerson

Cox plugs are generally very sturdy. I expect to put hundreds of flights on one. I have, over the years, had one or two which burned out the second a battery was connected, so there is some variability. I use a 2 volt 5 amp-hr Cyclon lead acid gel cell. I have about a 5 foot lead on it and a clip that fits Cox plugs as well as others. A major problem with starting Cox engines in not having the glow plug hot enough. It should be at least orange, and I run them more toward yellow.

ffkiwi

Up to a point I accept this- but TD 15's were noted for their ravenous appetite for glowheads when they were around-in normal routine use-and the later Special 15 Mk2 had a different head with a heavier .012 element and different internal profile to try and combat this-but of course was dropped when the FAI fuel rule came in around 1965. Of course people were using up to 50% nitro prior to that, and a 30% nitro fuel was considered mild by competition standards. When messing about with Babe Bees and the like in the 1970s, as mentioned in my earlier posts in this thread, 2V was death for 049 heads...........admittedly we were using 2V wet cells cut from from either motorcycle or car batteries-so lack of capacity was not an issue.

I would imagine a 5 foot lead would drop the voltage seem at the plug somewhat-it would be an interesting exercise to put a multimeter across the head when lit by your 2V Gates and measure the voltage under load. I'm in the process of completing a new compact field box with separate power panel and 2V Gates glowplug supplies (the latter with an in-line direct reading ammeter), so in a few weeks I may be able to put some real voltage and current figures up on the forum for a variety of plugs and heads....

ChrisM
'ffkiwi'

Boomerang1

I've used a single 'D' size nicad (4000 mAh) for more than 30 years on all my glow engines, including Cox engines when I had them.

Always reliable starts. - John.

Jim Thomerson

I flew a Cox 15 MK I (so to speak) on 10% nitro on a CL stunt airplane. It eventually blew a rod, but the glowhead was still fine.